The present invention relates to a tennis racket, a squash racket, and a badminton racket, and more particularly to a sports racket made of a fiber reinforced composite material capable of minimizing the shock exerted on the hand of a player using the sports racket.
Generally speaking, a sports racket of conventional type made of a fiber reinforced composite material comprises an outer shell of a fiber reinforced plastic. In the process of making such a sports racket as mentioned above, the outer shell is formed by means of placing intertwined fabric containing long fibers and thermosetting resin into a mold. As a result, the head portion and the handle portion of the racket are similar in terms of their cross-sectional structures. In view of a shock-transmitting system, the structural uniformity of the head portion and the handle portion, which are made into a unitized body, is responsible for an easy transmission of shock with a minimum of obstruction. It is readily apparent that the shock generated by an impact of a ball on the ball-hitting surface of the racket described above is subject to transmission easily from the head portion to the handle portion and then on to the hand which holds the racket.
In order to find a solution to the problem described above, a number of inventions have been developed and disclosed. For example, the inventor of Taiwan Patent No. 78201997 discloses a sports racket having means to prevent the shock of striking a ball from being transmitted to the handle. However, the constructional complexity of this invention makes it impractical from the standpoint of manufacture thereof and also results in a great deal of compromise of shock-absorbing effect thereof.
A sports racket having a shock-absorbing means in the form of elastic sponge is suggested by the inventor of Taiwan Patent No. 75210508. This disclosure emphasizes the use of spongy pieces of a high elasticity, which are inserted into the strings forming the ball-hitting surface so as to absorb the shock generated on the strings. However, the arrangement as such does not serve to mitigate the shock exerted on the racket frame.
The Taiwan Patent No. 78210299 discloses a sports racket having a frame structure capable of obstructing the transmission of shock, in which a plurality of grooves are constructed on the handle portion of the racket. Each of the grooves is covered with a shock-absorbing strap, which serves to hinder the shock wave. In fact, the transmission of the shock wave from the head frame to the grip portion can not be effectively averted by means of a structure such design as disclosed in this invention.
Additionally, the Taiwan Patent No. 78211558 discloses an improved structure for use in absorbing the shock exerted on a sports racket, which is characterized in that the edge of inner circumference of the head frame comprises a plurality of grooves, which are made into a unitized body of the head frame. A shock-absorbing rib bar is embedded in each of the grooves. It must be pointed out that the shock generated on the strings traversing the shock-absorbing rib bar can be effectively absorbed. However, the shock generated on those strings which do not traverse the shock-absorbing rib bar is not effectively mitigated. In addition, the inventor of this disclosure ignores the fact that the structural design as suggested results in a technical difficulty of stretching the strings across the head frame of the racket.
As far as a sports racket having an outer shell of fiber-reinforced plastic material is concerned, an effective method used to obstruct the transmission of the shock wave from the head frame to the handle portion of the racket has not been introduced so far.